IL-17-mediated osteolysis, which is detected in periodontitis and mouse models of arthritis or periodontal disease, is probably mediated by a receptor activator of NF-κB ligand (RANKL, TNFSF11, or osteoprotegerin ligand, OPGL) whose espression is induced by IL-17 (30, 31). The gene discussed is IL17A; the disease is arthritic joint disease.